A student places a seedling horizontally in darkness. Both the root and shoot continue growing.
Which statement explains their growth responses?
auxin slows upper root cells but speeds upper shoot cells
auxin speeds upper root cells but slows upper shoot cells
auxin speeds lower root cells but slows lower shoot cells
auxin slows lower root cells but speeds lower shoot cells
105 exam-style questions on Edexcel GCSE Biology 6.3 Plant hormones, covering 6.3.1 Plant hormones and tropisms and 6.3.2 Commercial uses of plant hormones. Each one has a worked solution and a mark scheme showing where the marks go.